// @(#)FiniteFIFOQueue.java   11/2003
// Copyright (c) 1998-2003, Distributed Real-time Computing Lab (DRCL) 
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package drcl.util.queue;

import java.util.*;
//import drcl.RecycleCan;

/**
 * Finite-length version of {@link FIFOQueue}.
 */
public class FiniteFIFOQueue extends FIFOQueue implements FiniteQueue
{
  //public static RecycleCan elementCan =new RecycleCan(_Element.class, 5, 5);
  int capacity = Integer.MAX_VALUE;

  public FiniteFIFOQueue()
  {}
                          
  public FiniteFIFOQueue(int capacity_)
  { capacity = capacity_; }
                          
  public void enqueue(double key_, Object element_)
  {
    if (isFull()) return;
    super.enqueue(key_, element_);
  }
  
  public boolean enqueueAfter(Object previousElement_, Object element_)
  {
    if (isFull()) return false;
    return enqueueAfter(previousElement_, element_);
  }
  
  public boolean enqueueAt(int pos_, double key_, Object element_)
  {
    if (isFull()) return false;
    return enqueueAt(pos_, key_, element_);
  }
  
  
  public void enqueue(Object element_)
  {
    if (isFull()) return;
    super.enqueue(element_);
  }
  
  public String oneline()
  {
    StringBuffer sb_ = new StringBuffer(
            super.toString() + "," + getLength() + "/" + capacity);
    
    for (_Element e_ = head.next; e_ != null; e_ = e_.next)
      sb_.append("-----" + e_.key + ":" + e_.obj);
    
    return sb_.toString();
  }

  public int getCapacity()
  { return capacity; }

  public void setCapacity(int cap_)
  {
    capacity = cap_;
    if (capacity <= 0) {
      capacity = 0;
      head.next = tail = null;
      length = 0;
    }
    else if (getLength() > capacity) {
      _Element e_= head;
      for (int i=0; i<capacity; i++, e_ = e_.next);
    
      e_.next = null;
      length = capacity;
      tail = e_;
    }
  }

  public boolean isFull()
  { return getLength() == capacity; }
}
